Electrospinning is an inexpensive method for creating continuous, randomly oriented, nanofibrous mats from a variety of synthetic and natural polymers. These characteristics, in conjunction with the beneficial intrinsic effects of increased surface area from its nanofibrous form, make electrospun polymers ideal for medical, packaging, agricultural, filtration, protective clothing, nanocomposites, and automotive applications (Huang, Z.-M.; Zhang, Y. Z.; Kotaki, M.; Ramakrishna, S.; Composites Science and Technology 2003, 63, (15), 2223-2253).
Chitosan, a derivative of chitin (the second most abundant, naturally occurring, organic material after cellulose) is environmentally friendly, non-toxic, biodegradable, and anti-bacterial. It has been demonstrated that chitosan can be electrospun into fibrous mats with the aid of an additional polymer in solution. The additional polymer is typically either polyethylene oxide (PEO) (see Duan, B.; Dong, C.; Yuan, X; Yao, K. J. Biomater. Sci., Polym. Ed. 2004, 15 (6), 797-811, Geng, X; Kwon, O.-H.; Jang, J. Biomaterials 2005, 26 (27), 5427-5432, Spasova, M.; Manolova, N.; Paneva, D.; Rashkov, I. e-Polymers 2004, 56, 1-12, Bhattarai, N.; Edmondson, D.; Veiseh, O.; Matsen, F. A.; Zhang, M. Biomaterials 2005, 26, 6176-6184) or poly(vinyl alcohol) (PVA) (see Min, B.-M.; Lee, S. W; Lim, J. N.; You, Y; Lee, T. S.; Kang, P. H.; Park, W. H. Polymer 2004, 45, 7137-7142). However, when formed from chitosan and PEO and/or PVA, the resulting fibrous mats tend to contain a high content of PEO/PVA fibers and the characteristics of the mats reflect the low proportion of chitosan, i.e., the mats do not possess some or all of the advantageous characteristics associated with chitosan.
There remains a need for fibrous mats having advantageous physical properties with utility in such processes as filtration of gas and/or liquid.